Digital Smile Design

The importance given to a beautiful smile is not new. The search for beauty can be traced to the earliest civilizations; both the Phoenicians (app 800 BC) and Etruscans (app 900 BC) carefully carved animal tusks to simulate the shape, form and hue of natural teeth [1]. Dentists who are experienced with cosmetic treatment know that subtle variations in the shapes of the teeth can mean the difference between successful treatment and hours of reshaping, contouring, shortening, or worst of all, restarting a case. Orthodontic treatment is performed on a significant population of patients who are not satisfied with what nature has given them in their smiles. People spend significant amounts of money with plastic surgeons and dermatologists to look different than what was their natural appearance. Do we as dentists always want to give patients a smile that mirrors what is often found in nature, such as crowded, overlapped, and twisted teeth, malocclusions or diastemas [2].


Esthetic Digital Smile Design Introduction and View
The importance given to a beautiful smile is not new. The search for beauty can be traced to the earliest civilizations; both the Phoenicians (app 800 BC) and Etruscans (app 900 BC) carefully carved animal tusks to simulate the shape, form and hue of natural teeth [1]. Dentists who are experienced with cosmetic treatment know that subtle variations in the shapes of the teeth can mean the difference between successful treatment and hours of reshaping, contouring, shortening, or worst of all, restarting a case. Orthodontic treatment is performed on a significant population of patients who are not satisfied with what nature has given them in their smiles.
People spend significant amounts of money with plastic surgeons and dermatologists to look different than what was their natural appearance. Do we as dentists always want to give patients a smile that mirrors what is often found in nature, such as crowded, overlapped, and twisted teeth, malocclusions or diastemas [2].
To minimize extended or failed delivery visits with removable or fixed prosthetics because of patient dissatisfaction with the smile design, several smile guides have been developed over the years. There are new, step-by-step techniques for incorporating digital technology into the smile design process that can be accomplished in approximately three to four minutes [3].
Aesthetic digital smile design DSD used to assist and improve diagnosis, communication, and predictability of treatment through an esthetic analysis of the assembly: Face, smile, periodontal tissue, and teeth. And the esthetics of the smile is related to the color, shape, texture, dental alignment, gingival contour, and the relationship of these with the face [4].

DSD Method and Protocol
DSD should first be an instrument to improve communication with the patient by showing the patient detailed images. On the monitor, the before and after photographs allow an index of predictability and point of comparison with the patient himself or herself. A milestone is the innovation of aesthetic clinical planning in aesthetic dentistry and prosthetic dentistry relating to dental technical analysis and planning, which among other things, can be integrated into diagnosis and planning for plastic and maxillofacial surgery [5]. The protocol first requires the acquisition of full-frame digital images as follows: full face with a wide smile, full face at rest, and retracted view of the full maxillary arch with teeth apart; and videos of the patient [4]. Video especially is capable of capturing the dynamic phases of the smile linked to its physiology (mimicry, phonetics, relationship between the teeth and lips).
Importing this vital data into the digital clinical file of the patient is complementary to the anamnesis because it is an integral part of the intra-and extraoral objective examination, and will subsequently be the subject of aesthetic analysis according to the main guiding principles. Therefore, we could define this as the third part of the methodology, which we will call analytical processing, during which the aesthetic composition of the smile, the determining morphological features of the face and smile, including the fundamental points of reference to be obtained from software such as face makers, will be mapped and processed. The next phase DOI: 10.26717/BJSTR.2020.31.005099 24188 in digital data processing is virtual planning by means of digital image editing: Wax-up, digital and analogue diagnosis, mock-up, and provisional and definitive restorations. The digital methodology used for photograph and image editing is very reliable, especially in communicating through images the ongoing clinical case to dental laboratories concerning functional and morphological adjustments, which is made even easier if accompanied by explanations and verbal comments [5].

Acquisition and Import of Digital Images
As stated earlier, the first phase of DSD entails the acquisition and import of photographs of the patient. If possible, these photographs should be taken with a digital SLR camera with semi-professional features and with a good illumination system. That in the analytical phase the photograph is a clinical and aesthetic diagnostic element that will form part of the patient's clinical history, which can be consulted by other specialists to establish an interdisciplinary vision. In view of this, the dentist/photographer must capture the photographs with the patient's head in a position that can be replicated in the future to verify topography in relation to smile design ( Figure 1). Most reliable position in which to photograph the patient's face is that relative to the aesthetic plan, that is the plane perpendicular (frontal) to the plane that runs at the center of the angle formed between the Frankfort horizontal plane and Camper's plane.  DSD built a measuring tool called Face Analogic Transfer Support ( Figure 2), which consists of a ruler with graduated millimeter and centimeter scales, which the patient can wear like a pair of glasses. Furthermore, for new photographs for the fabrication of mock-ups and PMMA models etc. it is useful to use a device such as a craniostat fixed to the headrest, which is integrated into our dental chair. If more accurate and detailed measurements of the teeth and gingival parameters are required, one can use digital calipers whose tips are placed at the cervical margin and incisal edge (the length of the tooth) or at the mesial and distal margins relative to the dental line (width of the tooth; Figure 3). These measurements when transmitted can be very effective in communication between the dentist and dental technician, whose manufacturing skills and expertise will be the most important to the end-result of this innovative method. It is necessary to bear in mind that the measurements expressed in millimeters in relation to the digital image produced by the digital processing, as well as the design of the dental contours, are not of much interest to patients, who desire a photograph of the first phase simulation, but the measurements represented as 3-D wax models and mock-ups tried in and analyzed in the patient's mouth will give you an idea of the delicate psychoaesthetic approach to the clinical case very important for aesthetic dentistry [5].

Analysis Components for Face and a Smile
In relation to the manner in which to portray the patient in a photograph, we should reflect on the aesthetic component of the face and the smile. For the objective aesthetic analysis, the focal length is modified, starting from the first photograph ( Figure 4).
For this parameter, the following classification criteria could be applied: macro-aesthetics (extra-oral analysis of the face).
b. mini aesthetics (extra-oral analysis of the mouth); and c. micro-aesthetics (intra-oral analysis of teeth and gingiva).
As regards the aesthetic analysis of the smile, the specific areas of the objective analysis that are pertinent to dentistry are as follows, based on that provided by a number of many authors:

Visagism and Facial Analysis
The final esthetic results may fail to meet the patient's expectations due to disharmony between the smile design and the patient's personality. The patient may feel that the restored teeth do not really "belong" to him or her. For decades, dental clinicians have sought to harmonize the shapes of the teeth with the entire face based on parameters such as gender, personality, and age; however, truly successful results have been elusive.
The visagism concept helps dental clinicians provide restorations that account not only for esthetics, but also for the psychosocial features of the created image, which affect patients' emotions, sense of identity, behavior, and self-esteem.
The shape of the face in relation to the four temperaments can be described as follows [6] (Figure 9): The first point that should be evaluated by a dentist is the patient's face, because the face has the original structure representing the human characters. In particular, the front face of the analysis affects how the construction of restoration. In this way, we want to take the features into consideration to concentrate on the face and hide abnormal structures.

Dentogingival Esthetics Analysis
Gingival margin placement-and the scalloped shape, in particular-are well discussed. As gingival heights are measured,

Dental Esthetics Analysis
Part of evaluating dental esthetics for smile design is choosing tooth shapes for patients based on their facial characteristics (e.g., long and dolichocephalic, or squarish and brachiocephalic). When patients present with a longer face, a more rectangular tooth within the esthetic range is appropriate. For someone with a square face, a tooth with an 80% width to length ratio would be more appropriate, but esthetic smiles could demonstrate ratios between 70 and 75% or 80 to 85% (Figure 14) [11][12][13][14].

Figure 14:
Acceptable width-to-length aspect ratios fall between 70 to 85%, with the ideal range between 80 to 85%. Natural portions demonstrate a lateral incisor between 60 to 70% of the width of the central incisor, which is larger than the golden proportion. However, a rule guiding proportions is that the canine and all teeth distal should be perceived to occupy less visual space ( Figure 16) [15,16].

Figure 15:
Lateral incisors are between 1 mm to a maximum of 25mm shorter than the central, with the canines slightly shorter than the central by between 0.5 to 1 mm.

Figure 16:
A rule guiding proportions is that the canine and all teeth distal should be perceived to occupy less visual space.
Another rule to help maintain proportions throughout the arch is 1-2-3-4-5; the lateral is 2/3 of the central and the canine is 4/5 of the lateral, with some latitude within those spaces ( Figure 17).
Finally, contact areas can be moved restoratively up to the root of the adjacent tooth. Beyond that orthodontics is require [3].       Figure 22), DSD offers important processing functions: the import, conversion and editing of dental shapes and types of dentition in the form of real images [5].  to assisting as a guide to diagnostic wax-up and consequently to the mock-up [4]. After the facial analysis the dental analysis was performed. A rectangle with the actual proportion of maxillary teeth and tooth outline were accomplished to analyze the shapes and width/length proportions of the pretreatment teeth ( Figure   23) [17,18].

Digital Image Editing and Planning
Then a rectangle with the ideal length/width proportion was placed over the teeth to compare the actual pretreatment proportions with the ideal ones ( Figure 23B). Furthermore, measurements in the digital photographs were performed and transferred to the dental cast to calibrate the digital ruler and guide the diagnostic wax-up ( Figure 23C-F). The final teeth outline, and gingival contour were planned ( Figure 23G), and the diagnostic wax-up was fabricated using DSD as a guide ( Figure 23H) [5].

Result
The DSD is a tool that assists with the diagnostics and allows the clinician to better predict treatment outcomes by using analysis of the esthetic principles in extra-and intraoral digital photographs [4]. Knowledge of smile design, coupled with new and innovative dental technologies, allows dentists to diagnose, plan, create, and deliver esthetically pleasing new smiles. Simultaneously, digital dentistry is enabling dentists to provide what patients demand: quick, comfortable, and predictable dental restorations that satisfy their esthetic needs [1]. In addition, implementation of a digital dentistry tool can improve communication among the patient, clinician, and dental laboratories and may become a common technique for all esthetic rehabilitations. The DSD is a simple technique that does not require specific equipment or software [4].